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PubMed1998

Trigeminal and olfactory chemosensory impact of selected terpenes.

In Experiment 1, four normosmics and four anosmics (three congenital, one idiopathic) provided odor and nasal pungency thresholds, respectively, for the following terpenes: delta3-carene, p-cymene, linalool, 1.8-cineole, and geraniol, plus the structurally related compound cumene. Additionally, all subjects provided nasal localization (i.e., right/left) and eye irritation thresholis. Trigeminally mediated thresholds (i.e., nasal pungency, nasal localization, and eye irritation) lay about three orders of magnitude above odor thresholds, which ranged between 0.1 and 1.7 ppm. The results implied uniform chemesthetic sensitivity across tasks and sites of impact. In Experiment 2, normosmics and anosmics provided odor and nasal pungency thresholds, respectively, for three pairs of isomeric terpenes: alpha- and gamma-terpinene, alpha- and beta-pinene, and R(+)- and S(-)-limonene. Odor thresholds ranged between 1.4 and 19 ppm, that is, about an order of magnitude higher than those of the previous terpenes, with no substantial differences between odor thresholds of members of a pair. Regarding chemesthetic impact, only alpha-terpinene evoked nasal pungency. The overall outcome suggests comparable trigeminal chemosensitivity between nose and eyes and between normosmics and anosmics, as shown before for homologous n-alcohols. It also lends support to a previously derived solvation model of the chemesthetic potency of airborne substances, and indicates the likely importance of certain molecular-size restrictions for effective trigeminal impact.

Acyclic Monoterpenes↗

PubMed2001

Effect of melting point of chiral terpenes on human stratum corneum uptake.

The effect of melting point of chiral penetration enhancers on their stratum corneum uptake was investigated. The pure enantiomers of a chiral compound often possess different melting points, and therefore dissimilar solubilities, to the racemate because of variations in their crystal structure. Two terpenes, menthol and neomenthol, saturated in propylene glycol/water, were applied to stratum corneum. Racemic menthol melts at approximately 33 degrees C, some 9 degrees C lower than the pure enantiomers, whereas racemic neomenthol melts at 26 degrees C higher than the study temperature, considered as the theoretical melting point of its enantiomers, which are both liquids. Terpene solubility increased with the propylene glycol content of the vehicle. The lower melting forms of both penetration enhancers possessed the highest solubility in every vehicle. Maximum stratum corneum uptake was obtained from formulations containing the lower melting forms of each enhancer in 60% w/w propylene glycol systems (highest concentration used). Compared with menthol, the larger melting point difference between optical forms of neomenthol produced bigger differences in their uptake. Thus melting point depression of menthol and neomenthol, by selection of the appropriate optical form, increased the amount of terpene delivered to the stratum corneum, in agreement with theoretical predictions.

Calorimetry, Differential Scanning↗

PubMed2002

Effect of different terpene-containing essential oils on permeation of estradiol through hairless mouse skin.

Purpose of the present investigation was to evaluate six terpene-containing essential oils for their capacity to promote permeation of estradiol (ES) through hairless mouse skin in vitro. Tests on cajuput, cardamom, melissa, myrtle, niaouli and orange oil, all used at the 10% w/w concentration in propylene glycol (PG), evidenced niaouli oil (NIA) as the best permeation promoter for ES. Tests on the main terpene components of NIA (1,8 cineole, alpha-pinene, alpha-terpineol and D-limonene), evaluated neat (10% w/w in PG) or in admixture, confirmed the better promoting activity of whole NIA. The present data point to the validity of complex terpene mixtures, such as that composing NIA, as transdermal penetration enhancers for moderately lipophilic drugs like ES.

Administration, Cutaneous↗

PubMed2003

The effects of Eucalyptus terpenes on hepatic cytochrome P450 CYP4A, peroxisomal Acyl CoA oxidase (AOX) and peroxisome proliferator activated receptor alpha (PPARalpha) in the common brush tail possum (Trichosurus vulpecula).

Eucalyptus leaves contain a high proportion of essential oils comprising of a complex mixture of monoterpenes such as 1,8-cineole, alpha-pinene, d-limonene and p-cymene. In this study, hepatic levels of microsomal lauric acid hydroxylase and peroxisomal cyanide-intensive palmitoyl coenzyme A oxidative activities were examined in livers of possums given an artificial diet consisting of the above monoterpenes for 10 days. These values were compared with those of possums fed a control diet containing only fruits and cereals. Peroxisomal cyanide-intensive palmitoyl coenzyme A oxidative activity was significantly higher in livers of treated possums relative to that of control possums (2.96+/-0.93 vs. 0.98+/-0.88 nmol/mg protein per min, P<0.01) (mean+/-S.D., n=4). A small increase in microsomal lauric acid hydroxylase activity was observed in the treated possum in comparison with the control group (4.40+/-0.85 vs. 3.60+/-0.48 nmol/mg protein per min) (mean+/-S.D., n=4). A higher NAD/ NADP ratio was observed in treated possums as compared with control possums (4.73+/-0.65 vs. 3.51+/-0.64 nmol/mg protein per min, P<0.05) (mean+/-S.D., n=4). No other statistically significant differences in pyridine nucleotide contents were found between control and treated possums. Northern blot analysis of mRNA from rat, human, terpene treated and control possum livers, using the corresponding koala cDNA probes, detected a more intense acyl CoA oxidase (AOX) mRNA band in livers of terpene fed possums. Negligible differences in the intensity of CYP4A and PPARalpha mRNA bands were observed between the two groups. These data suggest that Eucalyptus terpenes elevate hepatic AOX expression in possums.

Acyl-CoA Oxidase↗

PubMedDate not supplied

Mass transfer of terpenes through a silicone rubber membrane in a liquid-liquid contacting system.

Terpenoids are important compounds for the fragrance industry, and recently, biocatalytic methods have been developed to produce them from cheap monoterpenes, such as alpha-pinene oxide. The biotransformation of alpha-pinene oxide using resting cells of Pseudomonas fluorescens NCIMB 11671 produces isonovalal (cis-2-methyl-5-isopropylhexa-2,5-dienal), which is a fragrance. However, this biotransformation has technical problems including the following: alpha-pinene oxide undergoes autoxidation in water and light; it is hydrophobic and relatively toxic to the biocatalyst; and it suffers from product inhibition. Therefore, removal of isonovalal as it is formed should reduce its toxicity and increase volumetric productivity and production yield. Aqueous-organic two-phase (AOTP) systems can be used in the biotransformation of hydrophobic substrates and can protect biocatalysts from toxic substrates and products. However, the formation of stable emulsions makes further downstream processing and continuous operation difficult. One solution to these problems is to use a solid-phase membrane between the aqueous and organic phases in a Membrane Bioreactor for Biotransformation (MBB). Since there are no data in the literature on the behavior of terpenes and terpenoids with solid-phase membranes, or their mass transfer behavior, the objective of this work was to measure these parameters for a wide range of compounds so as to be able to design an MBB, and to gain a greater understanding of their behavior in these types of systems. Organic/aqueous (P (org) (aq)) and membrane/aqueous (P (mem) (aq)) partition coefficients were measured first, and subsequently used to quantify the overall mass transfer coefficients (k(ov)). The overall mass transfer coefficient (k(ov)) of alpha-pinene oxide through the membrane was found to be 2.5 x 10(-5) m x s(-1) using thicknesses of both 250 and 1,000 microm. Extraction kinetics were successfully described using a resistance-in-series model and were controlled by the aqueous boundary layer and/or membrane resistance (k(mem)), while organic film resistance played an insignificant role. Aqueous film resistance (k(aq)) was found to be the limiting step for mono- and diterpenes, and the effect of the hydrodynamics on k(ov) was successfully predicted using a Wilson plot. However, the extraction kinetics of larger terpenes, such as steroids, were influenced solely by the k(mem), suggesting that membrane diffusivity also depended on the size of the permeating molecule. Finally, the influence of other terpene byproducts on the flux of alpha-pinene oxide was investigated and found to decrease the flux into the organic phase by up to 10%.

Aldehydes↗

PubMed2000

The eye irritation and odor potencies of four terpenes which are major constituents of the emissions of VOCs from Nordic soft woods.

Eye goggles were used to estimate human thresholds for sensory eye irritation from four monoterpenes: (+)3-carene, (-)limonene and (+)alpha-pinene and (rac)alpha-terpineol all known as air pollutants emitted from wood. Only a ranking of the irritation thresholds relative to that of n-butanol is given. The measurements showed that the thresholds for eye irritation of the terpenes ranged from subthreshold to below 1,250 mg/m3. It appears that the irritation of 3-carene and limonene in contrast to the expectations was of the same size as or less than that of n-butanol. Too few subjects reported eye-irritation for alpha-pinene and alpha-terpineol to allow estimates of thresholds of these compounds which therefore have much less irritative potency than n-butanol, 3-carene, and limonene. The measurements of one terpene alcohol do not support the hypothesis that monoterpene alcohols, would have lower eye irritation threshold than monoterpene hydrocarbons. The sequence from strongest odorant to weakest was alpha-terpineol, 3-carene, n-butanol, limonene and alpha-pinene. In conclusion, the tested terpenes can probably be ruled out as cause of acute eye irritation indoors. The measured odor thresholds did not deviate from the few values reported in the literature.

Air Pollution, Indoor↗

PubMed2005

Laboratory studies on secondary organic aerosol formation from terpenes.

The formation of secondary organic aerosol (SOA) following the ozonolysis of terpene has been investigated intensively in recent years. The enhancement of SOA yields from the acid catalysed reactions of organics on aerosol surfaces or in the bulk particle phase has been receiving great attention. Recent studies show that the presence of acidic seed particles increases the SOA yield significantly (M. S. Jang and R. M. Kamens, Environ. Sci. Technol., 2001, 35, 4758, ref. 1; M. S. Jang, N. M. Czoschke, S. Lee and R. M. Kamens, Science, 2002, 298, 814, ref. 2; N. M. Czoschke, M. Jang and R. M. Kamens, Atmos. Environ., 2003, 37, 4287, ref. 3; M. S. Jang, B. Carroll, B. Chandramouli and R. M. Kamens, Environ. Sci. Technol., 2003, 37, 3828, ref. 4; Y. Iinuma, O. Böge, T. Gnauk and H. Herrmann, Atmos. Environ., 2004, 38, 761, ref. 5; S. Gao, M. Keywood, N. L. Ng, J. Surratt, V. Varutbangkul, R. Bahreini, R. C. Flagan and J. H. Seinfeld, J. Phys. Chem. A, 2004, 108, 10147, ref. 6). More detailed studies report the formation of higher molecular weight products in SOA (refs. 5 and 6; M. P. Tolocka, M. Jang, J. M. Ginter, F. J. Cox, R. M. Kamens and M. V. Johnston, Environ. Sci. Technol., 2004, 38, 1428, ref. 7; S. Gao, N. L. Ng, M. Keywood, V. Varutbangkul, R. Bahreini, A. Nenes, J. He, K. Y. Yoo, J. L. Beauchamp, R. P. Hodyss, R. C. Flagan and J. H. Seinfeld, Environ. Sci. Technol., 2004, 38, 6582, ref. 8) which could result in a non-reversible uptake of organics into the particle phase. Most of the past studies concentrated on the characterisation of the yields of enhanced SOA and its composition from ozonolysis of terpenes in the presence or absence of acidic and neutral seed particles. Recent findings from cyclohexene ozonolysis show that the presence of OH scavengers can also significantly influence the SOA yield. Our new results from the IfT chemistry department aerosol chamber on terpene ozonolysis in the presence of OH scavengers show that the presence of hydroxyl radical scavengers clearly reduces the amount of formed SOA. The OH scavenger strongly depletes the formation of oligomeric compounds in the particle phase in contrast to previous findings (M. D. Keywood, J. H. Kroll, V. Varatbangkul, R. Bahreini, R. C. Flagan and J. H. Seinfeld, Environ. Sci. Technol., 2004, 38, 3343, ref. 9). This result indicates that hydroxyl radicals play an important role in the formation of precursor compounds (e.g., hydroxy pinonaldehyde) for the particle phase heterogeneous acid catalysed reactions leading to the higher molecular weight compounds and thus the enhancement of SOA yields. Better understanding of the role of hydroxyl radicals in the formation of SOA is necessary to distinguish between the contribution of ozonolysis and hydroxyl radicals to the SOA yield. If the recent findings are a ubiquitous phenomenon in the atmosphere, current atmospheric and climate models might underestimate SOA formation yields, particle phase OC contents and its impact on the atmospheric radiation budget.

Aerosols↗

PubMed1973

The structure of novel C35 pentacyclic terpenes from Acetobacter xylinum.

A novel C(35) terpene and its monounsaturated analogue were isolated from cultures of Acetobacter xylinum, together with traces of their C(36) homologues. These substances were found to be hopane derivatives substituted by a five-carbon chain bearing four vicinal hydroxyl groups. For the parent hydrocarbon the term bacteriohopane is proposed. The elucidation of the structures utilized high-resolution mass spectrometry of the terpenes, degradation to C(32) hydrocarbons and detailed mass-spectrometric comparison of these with C(32) hydrocarbons synthesized from known pentacyclic triterpenes. High-resolution mass-spectral data of the terpenes are presented. N.m.r. data are in agreement with the proposed structures, which are further supported by the isolation from the same organism of 22-hydroxyhopane and derivative hopene(s).

Chromatography, Gas↗

PubMed1996

Identifying functional domains within terpene cyclases using a domain-swapping strategy.

Cyclic terpenes and terpenoids are found throughout nature. They comprise an especially important class of compounds from plants that mediate plant- environment interactions, and they serve as pharmaceutical agents with antimicrobial and anti-tumor activities. Molecular comparisons of several terpene cyclases, the key enzymes responsible for the multistep cyclization of C10, C15, and C20 allylic diphosphate substrates, have revealed a striking level of sequence similarity and conservation of exon position and size within the genes. Functional domains responsible for a terminal enzymatic step were identified by swapping regions approximating exons between a Nicotiana tabacum 5-epi-aristolochene synthase (TEAS) gene and a Hyoscyamus muticus vetispiradiene synthase (HVS) gene and by characterization of the resulting chimeric enzymes expressed in bacteria. While exon 4 of the TEAS gene conferred specificity for the predominant reaction products of the tobacco enzyme, exon 6 of the HVS gene conferred specificity for the predominant reaction products of the Hyoscyamus enzyme. Combining these two functional domains of the TEAS and HVS genes resulted in a novel enzyme capable of synthesizing reaction products reflective of both parent enzymes. The relative ratio of the TEAS and HVS reaction products was also influenced by the source of exon 5 present in the new chimeric enzymes. The association of catalytic activities with conserved but separate exonic domains suggests a general means for generating additional novel terpene cyclases.

Alkyl and Aryl Transferases↗

PubMed2000

Assessment of terpene levels and workers' exposure in sawmills with Long Path FTIR.

This study focuses on the assessment of airbone terpene levels in the saw shed of a sawmill. It describes results and practical aspects concerning the indoor use of a Long Path FTIR measurement technique that was primarily developed for emission monitoring in outdoor applications. The results from FTIR sampling are compared with results from personal adsorbent samples and a point monitoring PID instrument. The Long Path FTIR light path covered the entire length of the saw shed in the mill. This enabled measurement of real-time, path integrated concentrations along the beam path. The four monoterpenes alpha-pinene, beta-pinene, delta 3-carene, and limonene were identified along with ethanol. Quantification was achieved by using a classical least square evaluation software. The limit of detection of the individual terpenes was 1.5 mg/m3, or 0.27 ppm. The terpene levels in the sawmill fluctuated significantly and the average concentrations exceeded the Swedish 8-hour PEL (150 mg/m3, 25 ppm). Peak levels were recorded near the Swedish short-term exposure limit (300 mg/m3, 50 ppm). Results from simultaneous sampling with personal adsorbents, analyzed by GC, showed good agreement with the long path FTIR sampling (r = 0.98, n = 7). The FTIR application described is general in nature and offers a stable and convenient form for continuous monitoring over extended periods of times, and the conclusions drawn from this study may well be applied in other similar surveys.

Air Pollutants, Occupational↗

PubMed2026

Haplotype-specific expression of a terpene synthase underlies linalool variation in the grapevine cultivar Riesling.

Grapevine cultivars vary widely in monoterpenoid content, yet the genetic and regulatory mechanisms underlying this variation remain poorly characterized beyond highly aromatic Muscat types. We profiled free volatiles and monoterpenoid glycosides in a Riesling × Cabernet Sauvignon F1 mapping population, revealing extensive variation and transgressive segregation consistent with multigenic control. QTL mapping identified 70 significant loci associated with 48 volatile compounds and monoterpene glycosides, including two major QTLs explaining 33.6% and 33.4% of phenotypic variance in (3S)-linalool accumulation. Integration of haplotype-resolved transcriptomics with metabolite data, enabled by a chromosome-scale diploid Riesling genome assembly, resolved a (3S)-linalool/nerolidol synthase cluster on chromosome 10 and identified VviTPS54 as the strongest candidate underlying linalool variation. VviTPS54 exhibited haplotype-specific expression strongly correlated with (3S)-linalool accumulation across genotypes, while no QTL was detected at the 1-deoxy-D-xylulose-5-phosphate synthase 1 (VviDXS1) locus previously identified in Muscat cultivars. In addition, VviDXS1 expression was not correlated with terpene levels, indicating that regulatory variation within terpene synthase clusters, rather than methylerythritol phosphate (MEP) pathway flux, drives monoterpenoid composition in this population. These results establish regulatory variation of terpene synthases as a key mechanism underlying monoterpenoid diversity in grapevine and demonstrate that resolving such variation requires haplotype-phased genome assemblies coupled with haplotype-resolved transcriptomics to detect allele-specific expression differences at complex, heterozygous loci.

Grapevine↗

PubMed2006

Identification and characterization of the acyclic terpene utilization gene cluster of Pseudomonas citronellolis.

The catabolism of citronellol and geraniol [acyclic terpene utilization (Atu) pathway] was investigated in Pseudomonas citronellolis. A 13.3-kb genomic DNA fragment was cloned and harboured a putative regulator gene atuR and a gene cluster consisting of eight genes (atuABCDEFGH). Sequence analysis of the atu gene products showed a high degree of amino acid similarity (78-91% identity) to products of a similar gene cluster previously identified in Pseudomonas aeruginosa. Insertion mutagenesis in atuA resulted in inability of the bacteria to utilize acyclic terpenes as a sole source of carbon and energy and confirmed the involvement of atuA in the Atu pathway. Western blot analysis of wild-type and atuA mutant cells of P. citronellolis and P. aeruginosa for biotin-containing proteins enabled the identification of geranyl-CoA carboxylase (GCase), which is the key enzyme of the Atu pathway. GCase subunits were encoded by atuC and atuF. Putative functions for the other Atu proteins in the catabolic pathway of acyclic terpenes are discussed.

Bacterial Proteins↗

PubMed2025

Integrated genomic, transcriptomic, and metabolomic analyses of Chrysanthemum aromaticum provide insights into the volatile terpene biosynthesis.

Chrysanthemum aromaticum is renowned for its uniformly emitted strong and attractive scent, primarily attributed to volatile terpenes. Despite its commercial and horticultural significance, the molecular mechanisms underlying volatile terpene production in C. aromaticum remain largely unexplored. Here, we present the haplotype-resolved genome assembly of C. aromaticum, with a total size of 3.10 Gb, comprising nine anchored chromosomes with a contig N50 of 30.66 Mb and a scaffold N50 of 350.58 Mb. Phylogenetic analyses revealed a distant relationship between C. aromaticum and C. indicum, suggesting that C. aromaticum likely represents a distinct species rather than a variety of C. indicum. Through integrated genomic, transcriptomic, metabolomic, and biochemical analyses, we identified seven TPS involved in monoterpene biosynthesis and six TPS for sesquiterpene biosynthesis. Notably, comparative genomic analysis revealed a gene cluster for α-bisabolol biosynthesis in C. aromaticum, which has specifically expanded in Chrysanthemum species through tandem gene duplications, contributing to the elevated accumulation of α-bisabolol in the leaves of C. aromaticum. Our study provides important insights into the biosynthesis of volatile terpenes, highlighting the genetic basis for C. aromaticum's unique aromatic profile.

Chrysanthemum↗

PubMed2006

Identification of genes and proteins necessary for catabolism of acyclic terpenes and leucine/isovalerate in Pseudomonas aeruginosa.

Geranyl-coenzyme A (CoA)-carboxylase (GCase; AtuC/AtuF) and methylcrotonyl-CoA-carboxylase (MCase; LiuB/LiuD) are characteristic enzymes of the catabolic pathway of acyclic terpenes (citronellol and geraniol) and of saturated methyl-branched compounds, such as leucine or isovalerate, respectively. Proteins encoded by two gene clusters (atuABCDEFGH and liuRABCDE) of Pseudomonas aeruginosa PAO1 were essential for acyclic terpene utilization (Atu) and for leucine and isovalerate utilization (Liu), respectively, as revealed by phenotype analysis of 10 insertion mutants, two-dimensional gel electrophoresis, determination of GCase and MCase activities, and Western blot analysis of wild-type and mutant strains. Analysis of the genome sequences of other pseudomonads (P. putida KT2440 and P. fluorescens Pf-5) revealed candidate genes for Liu proteins for both species and candidate genes for Atu proteins in P. fluorescens. This result concurred with the finding that P. fluorescens, but not P. putida, could grow on acyclic terpenes (citronellol and citronellate), while both species were able to utilize leucine and isovalerate. A regulatory gene, atuR, was identified upstream of atuABCDEFGH and negatively regulated expression of the atu gene cluster.

Acyclic Monoterpenes↗

PubMed2004

Terpenic and phenolic glycosides from leaves of Breynia officinalis HEMSL.

From the leaves of Breynia officinalis, collected on Okinawa Island, six terpenic glucosides and six phenolic glycosides were isolated. Two of the terpenic glucosides were found to be known, and they were identified as turpinionoside B and betulalbuside A. The structures of the remaining terpenic glucosides were elucidated to be megastigmane glucosides, named breyniaionosides A-D, using spectroscopic analyses. The absolute structure of breyniaionoside D was determined using the modifed Mosher's method. The absolute structure of the known compound betulalbuside A was determined for the first time in this study. Six phenolic glycosides were found to be arbutin and its derivatives. Two known compounds were found to be robustaside A and eximine. New compounds were named isorobustaside A, and breyniosides A and B, and their structures were elucidated from spectroscopic evidence.

Euphorbiaceae↗

PubMed2000

Effects of branched cyclodextrins on the solubility and stability of terpenes.

In order to investigate the application potential of branched CDs, the solubilizing ability and the stabilizing ability of G2-betaCD and GUG-betaCD were investigated by using twelve terpenes (d-limonene, myrcene, terpinolene, geraniol, l-menthol, nerol, alpha-terpineol, citral, d-citronellal, l-perillaldehyde, (R)-l-carvone, and menthone) as guest compounds. G2-betaCD and GUG-betaCD showed more solubilizing ability for these twelve terpenes than betaCD, and the ability of GUG-betaCD was almost the same as that of G2-betaCD. The stabilizing ability of terpene-GUG-betaCD complexes was different from that of G2-betaCD. GUG-betaCD was superior to G2-betaCD, especially in the solid state. This result may have been caused by the difference in structure of side chain, namely the hydroxymethyl group in G2-betaCD and the carboxyl group in GUG-betaCD.

Cyclodextrins↗

PubMedDate not supplied

Secondary metabolite concentrations and terpene emissions of Scots pine xylem after long-term forest fertilization.

Secondary compounds are known to be associated with the resistance of conifer xylem against insects and fungi. The effects of long-term forest fertilization with nitrogen (N) or with N, calcium (Ca), and phosphorus (P) on secondary compounds in the xylem of 50-yr-old Scots pine (Pinus sylvestris L.) trees were examined. Xylem samples were collected from trees growing in three locations in southern Finland: Vilppula, Padasjoki, and Punkaharju. Forests were fertilized every fifth (Vilppula and Padasjoki) or tenth (Punkaharju) year since the 1950s. We compared concentrations of individual and total monoterpenes and resin acids in the heartwood and sapwood of Scots pine. Terpene emissions were analyzed from the sapwood and total phenolics from the heartwood. Fertilization did not have any significant effect on the concentrations and emissions of xylem monoterpenes. Concentrations of several individual terpenes in sapwood were positively correlated with the corresponding terpene emission. The concentrations of individual resin acids (i.e., abietic and dehydroabietic) decreased significantly in Punkaharju, but increased in the sapwood of N-fertilized trees compared with control ones at Padasjoki and Vilppula. The concentrations of resin acids in the heartwood were not significantly affected by fertilization. Both fertilization treatments decreased the total phenolic concentrations in the heartwood of trees growing in Padasjoki. There was a significant positive correlation between the total phenolics and total resin acid concentration. Overall, resin acids and phenolics seemed be more responsive than monoterpenes to N treatment. These results suggest that forest fertilization might cause slight changes in secondary compound concentrations of xylem, and thus might have significance in the decay resistance of wood.

Animals↗

PubMedDate not supplied

Sample preparation and determination of ginkgo terpene trilactones in selected beverage, snack, and dietary supplement products by liquid chromatography with evaporative light-scattering detection.

Ginkgo biloba leaf extract has been widely used in dietary supplements and more recently in some foods and beverages. Sample preparation procedures for determination of ginkgo terpene trilactones (including bilobalide and ginkgolides A, B, C, and J) in various sample matrixes were developed in this study. Ginkgo leaves and capsules were extracted with 5% KH2PO4 aqueous solution under sonication. Tea bags were extracted with boiling water, whereas drink samples were taken directly from the bottles. After filtration and the addition of NaCl to approximately 30% (w/v), the terpene trilactones in aqueous solutions were quantitatively extracted with ethyl acetate-tetrahydrofuran (4 + 1, v/v). Puff samples (a cereal-based fried snack item) were first defatted by using hexane or by using supercritical fluid extraction and then extracting under sonication with methanol-acetic acid (99 + 1, v/v). After evaporation of the organic phase, the terpene trilactones were redissolved in methanol and determined on a C18 reversed-phase column by liquid chromatography (LC) with evaporative light-scattering detection. The method of standard additions and gas chromatography with flame ionization detection were used for method validation. For most samples, the relative standard deviation was <10%. The identities of target compounds in ginkgo leaves and drink samples were confirmed by LC/electrospray ionization-tandem mass spectrometry.

Algorithms↗